Multifaceted Search with Facet Hierarchy

2. The method of claim 1, wherein the selected facet is a facet topic of a parent facet in the facet hierarchy and the search facet topic is a facet topic of a child facet of the parent facet.

3. The method of claim 1, further comprising displaying in the updated facet hierarchy interface a representation of the selected facet topic and the representation of the search facet topic in a hierarchical arrangement according to the facet hierarchy.

4. The method of claim 1, wherein updating the facet hierarchy interface comprises limiting a set of facet topics represented by the facet hierarchy interface based on a likeliness data structure, the likeliness data structure specifying paths between facets.

5. The method of claim 4, wherein the likeliness data structure comprises a trie representing the paths between facets.

6. The method of claim 1, wherein the facet topic selection indicates a selection of multiple facet topics from the plurality of facet topics.

8. The method of claim 7, wherein the selected facet topic is a facet topic of a parent facet in the facet hierarchy and the search facet topic is a facet topic of a child facet of the parent facet.

9. The method of claim 7, further comprising displaying in the updated facet hierarchy interface a representation of the selected facet topic and the representation of the search facet topic in a hierarchical arrangement according to the facet hierarchy.

10. The method of claim 7, wherein updating the facet hierarchy interface comprises limiting a set of facet topics represented by the facet hierarchy interface based on a likeliness data structure, the likeliness data structure specifying paths between facets.

11. The method of claim 7, wherein the facet topic selection indicates a selection of multiple facet topics from the plurality of facet topics.

14. The method of claim 12, wherein the facet hierarchy is determined according to a facet hierarchy definition that defines a facet group, the facet group comprising a parent facet and a child facet.

15. The method of claim 14, wherein the selected facet topic is a facet topic of the parent facet in the facet hierarchy and the search facet topic is selected for display in the updated facet hierarchy interface based on being a facet topic of the child facet.

16. The method of claim 12, further comprising displaying in the updated facet hierarchy interface a representation of the selected facet topic and the representation of the search facet topic in a hierarchical arrangement according to the facet hierarchy.

17. The method of claim 14, wherein the facet hierarchy definition defines a plurality of facet groups and wherein the first faceted query comprises a faceted query expression to OR facet topics selected from within a facet group and facet topics selected across facet topic groups.

19. The method of claim 18, wherein the first faceted query comprises an AND expression to AND a plurality of facet group expressions.

20. The method of claim 12, wherein the first facet topic selection indicates a selection of multiple facet topics from the plurality of facet topics.